For decades now, synthetic polymers have been used in hundreds of products in all areas of human and animal life, ranging from industrial coatings to food additives to molded articles. Many of such polymers are technically defined as addition polymers generally prepared from polymerizable compounds known as ethylenically unsaturated polymerizable monomers. Upon reaction under standard polymerization conditions, the monomers are linked together in a long chain backbone in repeating units to form a high molecular weight compound.
Most polymers are prepared having certain properties which are provided by specific moieties or groups appended to the polymeric backbone. In some instances, such appended moieties are added to the backbone after polymerization using various known chemical reactions and reagents. This is often impossible or impractical, however, where the chemistry needed for appending the groups adversely affects the polymer itself or already appended groups in the polymer. Thus, polymer chemists and other researchers often try to find ways of appending desired groups to the polymerizable monomers prior to polymerization.
The preparation of ethylenically unsaturated polymerizable monomers is normally achieved using standard techniques such as those described by Rodriguez in his well known textbook entitled Principles of Polymer Systems, Hemisphere Publishing Co., 1982. That is, one or more vinyl moieties are introduced into the compound by the selective oxidation of isobutylene followed by esterification.
While such techniques have been generally successful in the past, there remain serious limitations on what types of groups can be appended to polymeric backbones either prior or subsequent to polymerization. The conditions of polymerization or monomer synthesis often adversely affect groups which one might want to append, such as thiols, groups with free hydroxyls or nucleotides. Thus, there is a continuing need for inexpensive, rapid and effective means for preparing polymerizable monomers which have a wide variety of potential appended groups.
The catalytic activity of enzymes is well known. It is also well known that certain microorganisms possess enzymes which can be used as biocatalysts outside of the host to prepare useful compounds from starting materials that act as substrates for the enzymes.
For example, biocatalysis is described for a porcine pancreatic lipase by Zaks et al (Science, 224, pp. 1249-1251, 1984). A strain belonging to the genus Corynebacterium is known to provide certain fatty acids from an n-paraffin according to U.S. Pat. No. 3,823,070. Alkenes are oxidized by a strain of Methylococcus capsulatus according to U.S. Pat. No. 4,594,324. Other biocatalytic reactions, including the production of optically active compounds, are described for example in U.S. Pat. Nos. 4,008,125 and 4,415,657.
EP-A-0 280 232 (published Aug. 9, 1988) describes and claims the use of a biocatalyst derived from Corynebacterium oxydans to make a monoacetate by reacting a diol with an ester of acetic acid. Moreover, U.S. Ser. No. 229,959 (filed Aug. 9, 1988 by Green, Goodhue and Olyslager) describes and claims the use of use of a biocatalyst derived from Corynebacterium oxydans to make a chiral hydroxycarboxylic acid from a prochiral diol.
While these two references describe important advances in the art of biocatalysis, they fail to show how to provide ethylenically unsaturated polymerizable monomers. Because there is considerable unpredictability in the preparation of such monomers, there is no certainty that the same procedures used for preparing saturated compounds can be used to make unsaturated ones. Conditions which favor desired reactions of saturated compounds often adversely affect unsaturated ones. In fact, in most chemical synthetic procedures, care must be taken to avoid saturating a double bond when preparing monomers.
There continues to be a need for an economical and simple way to make unsaturated polymerizable compounds which can have a wide variety of appended groups. It would be particularly desirable to avoid standard chemical synthetic methods and their attending problems, and to use biocatalysis.